Edge service integrated using Spring Cloud Gateway

Author: Nasruddin

.idea/compiler.xml

@@ -45,8 +45,6 @@ services:
     build: ../microservices/course-composite-service
     image: javatab/course_composite_service:v1
     mem_limit: 512m
-    ports:
-      - "8080:8080" # Only this service will be exposed to outside containers so no port binding for above images
     environment:
       - SPRING_PROFILES_ACTIVE=docker
 
@@ -112,5 +110,11 @@ services:
   eureka:
     build: ../spring-cloud/eureka-server
     mem_limit: 512m
+
+  gateway:
+    environment:
+      - SPRING_PROFILES_ACTIVE=docker
+    build: ../spring-cloud/gateway
+    mem_limit: 512m
     ports:
-      - "8761:8761"
+      - "8080:8080"

.idea/encodings.xml

@@ -9,22 +9,9 @@
 
 @SpringBootApplication
 @ComponentScan("io.javatab")
-public class SearchServiceApplication implements CommandLineRunner {
-
-	private ElasticRepository repository;
-
-	public SearchServiceApplication(ElasticRepository repository) {
-		this.repository = repository;
-	}
+public class SearchServiceApplication {
 
 	public static void main(String[] args) {
 		SpringApplication.run(SearchServiceApplication.class, args);
 	}
-
-	@Override
-	public void run(String... args) throws Exception {
-		repository.deleteCourse().block();
-		repository.createCourse(new SearchEntity("Course Name", 1))
-				.subscribe(indexResponse -> System.out.println("Index Response " + indexResponse));
-	}
 }

docker/docker-compose.yml

@@ -27,5 +27,6 @@
         <module>microservices/student-service</module>
         <module>microservices/vote-service</module>
         <module>spring-cloud/eureka-server</module>
+        <module>spring-cloud/gateway</module>
     </modules>
 </project>

microservices/search-service/src/main/java/io/javatab/microservices/core/search/SearchServiceApplication.java

@@ -0,0 +1,17 @@
+# stage 1
+# Start with a base image containing Java runtime
+# TODO :: Upgrade to slim jre version for 17 once available
+FROM openjdk:17-alpine as builder
+WORKDIR application
+ARG JAR_FILE=target/*.jar
+COPY ${JAR_FILE} application.jar
+RUN java -Djarmode=layertools -jar application.jar extract
+
+# the second stage of our build will copy the extracted layers
+FROM openjdk:17-alpine
+WORKDIR application
+COPY --from=builder application/dependencies/ ./
+COPY --from=builder application/spring-boot-loader/ ./
+COPY --from=builder application/snapshot-dependencies/ ./
+COPY --from=builder application/application/ ./
+ENTRYPOINT ["java", "org.springframework.boot.loader.JarLauncher"]

pom.xml

@@ -0,0 +1,54 @@
+package io.javatab.springcloud.gateway.configuration;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.actuate.health.CompositeReactiveHealthContributor;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.ReactiveHealthContributor;
+import org.springframework.boot.actuate.health.ReactiveHealthIndicator;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.reactive.function.client.WebClient;
+import reactor.core.publisher.Mono;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import static java.util.logging.Level.FINE;
+
+@Configuration
+public class HealthCheckConfiguration {
+
+    private static final Logger LOG = LoggerFactory.getLogger(HealthCheckConfiguration.class);
+
+    private WebClient webClient;
+
+    @Autowired
+    public HealthCheckConfiguration(WebClient.Builder webClientBuilder) {
+        this.webClient = webClientBuilder.build();
+    }
+
+    @Bean
+    ReactiveHealthContributor healthCheckMicroservices() {
+
+        final Map<String, ReactiveHealthIndicator> registry = new LinkedHashMap<>();
+
+        registry.put("course", () -> getHealth("http://course"));
+        registry.put("student", () -> getHealth("http://student"));
+        registry.put("vote", () -> getHealth("http://vote"));
+        registry.put("search", () -> getHealth("http://search"));
+        registry.put("course-composite", () -> getHealth("http://course-composite"));
+
+        return CompositeReactiveHealthContributor.fromMap(registry);
+    }
+
+    private Mono<Health> getHealth(String baseUrl) {
+        String url = baseUrl + "/actuator/health";
+        LOG.debug("Setting up a call to the Health API on URL: {}", url);
+        return webClient.get().uri(url).retrieve().bodyToMono(String.class)
+                .map(s -> new Health.Builder().up().build())
+                .onErrorResume(ex -> Mono.just(new Health.Builder().down(ex).build()))
+                .log(LOG.getName(), FINE);
+    }
+}